The invention relates to a loudspeaker of the type having an annular permanent magnet system with an annular moving coil connected to a loudspeader diaphragm:
A loudspeaker of the particular generic type which makes it possible to achieve a relatively slim design is already known (German Periodical: Funkschau [Radio View] 1978, No. 1, pages 21 (63) to 24 (66)). This so-called "Manger" sound converter has a relatively large and therefore heavy annular permanent magnet which is arranged on a support for the magnetic return and within which moves the moving coil fastened to the plane round diaphragm disc and centered relative to the permanent magnet by means of a restoring force, albeit only slight. Furthermore, the diaphragm is a complex and therefore a relatively expensive multi-layer diaphragm.
An object of the invention is to design a loudspeaker of the particular generic type, so that, whilst at the same time ensuring a comparable sound quality, it has a simpler and more cost-effective construction, a smaller constructional volume, especially a slimmer design, and a lower weight.
In a loudspeaker of the particular generic type, this object is achieved by providing the moving coil as an annular coil which carries a thin walled annular core of amorphous metal at its outer surface and which surrounds the permanent magnet system which is composed of two permanent magnet rings spaced from one another by means of a soft-magnetic annular intermediate disk and with like poles facing one another.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.